Q&A – What is the brown spot on our maple leaves?
Question:
We live in north-east Ohio. Our maple trees have some sort of brown spots on the leaves. What is it? Is there anything I can do to help them be healthier?
Answer:
Retired UT Extension Agent Mike Dennison references an extension publication from Ohio State University. There are three common causes for brown leaf spots on maples in Ohio: oak leaf blister, tar spot, and phyllosticta leaf spot. Jim Crowder from Memphis Botanic Garden says that usually leaf spots that only cover 10%-20% of the leaf do not affect a mature tree and you should not worry about it. If you have leaf spot that is affecting half or more of the leaf area, have an arborist take a look at it. Because it is a fungus you can spray fungicide on a preventative basis, but that is only possible on a small tree, it is not possible on a large tree.
The publication Mike referred to is available here: Leaf Diseases on Ornamental Trees and Shrubs
Related Resources:
Management of leaf spot diseases of trees and shrubs
Oak Leaf Blister
Maple Tar Spot
We live in north-east Ohio. Our maple trees have some sort of brown spots on the leaves. What is it? Is there anything I can do to help them be healthier?
Answer:
Retired UT Extension Agent Mike Dennison references an extension publication from Ohio State University. There are three common causes for brown leaf spots on maples in Ohio: oak leaf blister, tar spot, and phyllosticta leaf spot. Jim Crowder from Memphis Botanic Garden says that usually leaf spots that only cover 10%-20% of the leaf do not affect a mature tree and you should not worry about it. If you have leaf spot that is affecting half or more of the leaf area, have an arborist take a look at it. Because it is a fungus you can spray fungicide on a preventative basis, but that is only possible on a small tree, it is not possible on a large tree.
The publication Mike referred to is available here: Leaf Diseases on Ornamental Trees and Shrubs
Related Resources:
Management of leaf spot diseases of trees and shrubs
Oak Leaf Blister
Maple Tar Spot